This invention relates to imaging machines and, in particular, to a photoelectrophoretic imaging machine. More specifically, this invention relates to new and improved machines for implementing the photoelectrophoretic process.
In the photoelectrophoretic imaging process black and white or full color images are formed through the use of photoelectrophoresis. An extensive and detailed description of the photoelectrophoretic process is found in U.S. Pat. Nos. 3,384,448 and 3,384,565 to Tulagin and Carreira, 3,383,993 to Yeh and 3,384,566 to Clark, which disclose a system where photoelectrophoretic particles migrate in image configuration providing a visual image at one or both of two electrodes between which the particles suspended within an insulating carrier is placed. The particles are electrically photosensitive and are believed to bear a net electrical charge while suspended which causes them to be attracted to one electrode and apparently undergo a net change in polarity upon exposure to activating electromagnetic radiation. The particles will migrate from one of the electrodes under the influence of an electric field through the liquid carrier to the other electrode.
The photoelectrophoretic imaging process is either monochromatic or polychromatic depending upon whether the photosensitive particles within the liquid carrier are responsive to the same or different portions of the light spectrum. A full-color polychromatic system is obtained, for example, by using cyan, magenta and yellow-colored particles which are responsive to red, green and blue light respectively.
The photoelectrophoretic imaging system disclosed in the above-identified patents may utilize a transparent flat electrode configuration for one of the electrodes used in establishing the electrical field across the imaging suspension. A photoelectrophoretic imaging machine having a stationary flat transparent electrode over which roller electrodes travel for rapid production of images in a sequential manner has been suggested in the prior art as described, for example, in U.S. Pat. No. 3,644,035. A belt drive mechanism in a photoelectrophoretic imaging machine is disclosed in Egnaczak et al. U.S. Pat. No. 3,647,290.